The present invention relates to a new tetrahydropyridazine derivative and a herbicide containing it as the active ingredient.
It has been known hitherto that some tetrahydropyridazine derivatives have a herbidical effect. For example, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Sho 53-40785 discloses that N-substituted hydrazine derivatives having a structure represented by the following formula have a herbicidal effect: ##STR2## wherein R represents a hydrogen atom or carboethoxy group, and X represents a chlorine atom or bromine atom.
J. P. KOKAI No. Sho 59-82372 discloses that hexa hydropyridazinecarboxylic acid derivatives represented by the following formula have a herbicidal effect: ##STR3## wherein X represents a chlorine atom or bromine atom, Y represents an oxygen atom or sulfur atom, R.sup.1 represents a lower alkyl group, lower alkenyl group or lower alkynyl group, and R.sup.2 represents a lower alkyl group.
However, these compounds were not always satisfactory in fact, since their herbicidal effect was insufficient and, therefore, they had to be used in a large amount, and the safety of them for crops was insufficient.